Another theory is that repetitive small trauma to the muscle helps to create a “trigger point ... upper body begins to slump forward. To raise your head to see, you use your upper trapezius ...

In this open, uncontrolled trial, 20 patients with upper trapezius muscle trigger point pain and ipsilateral masseter muscle pain received a single trigger point injection of 2% lidocaine solution ...

Active MTrPs were found in the infraspinatus muscle in 56 subjects and in the upper trapezius muscle in 42 subjects. In addition, active MTrPs were highly prevalent in the middle trapezius (n = 31 ...